<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>05_JS流程控制</title>
</head>
<body>
<script>
    //1.顺序结构
    console.log('1');
    console.log('2');
    console.log('3');
    //2.分支结构
    let uname = 'tom';
    if(!uname){
        //alert('请输入用户名!');
    }else{
        //alert('欢迎'+uname+'回归!');
    }
    //3.选择分支
    let gender = 11;
    switch (gender){
        case 1:
           console.log('男');break;
        case 0:
            console.log('女');break;
        default:
            console.log('未知');
    }
    //4.循环结构
    let names = ['tom','jack','rose'];
    for(let i = 0; i < names.length; i++){
        console.log(names[i]);
    }
    //如果用var定义循环变量i,循环结束后在此处仍能打印出i的值
    //但如果用let定义,就会报错:变量i不存在!
    //console.log(i);

    //5.增强for循环
    //let n为每轮循环取出的值 names被遍历的数组
    for(let n of names){
        console.log(n);
    }

</script>
</body>
</html>